I found this note on “Don’t listen to what your customers say, watch how they behave” by Rita Gunther McGrath very thought-provoking. Please note particularly:
“I am often asked by companies with whom I work whether focus groups, surveys or customer panels are useful in learning what customers want and more importantly, what they will pay for. Sure, these techniques are helpful and sometimes can lead to useful insights. But it is usually a huge strategic mistake to base investment decisions or innovation projects on data gathered through these means. Why? A benign explanation is that we are all massively unaware of what really does drive our behavior. A less charitable explanation is that when people are asked questions, they tend to respond the way they think the person asking would like them to (which is one reason why doctors always double the number of drinks per day patients report consuming).”
See also a similar perspective from Russ Ackoff: There is no point in asking consumers -who do not know what they want – to say what they want.